The Effect of Ankle Dorsiflexion Range of Motion on Lower Extremity Injuries

Context: The weight-bearing lunge test is an effective method in determining the range of motion of ankle dorsiflexion. Despite the lack of research for this test it does have good inter-rater and intra-rater reliability. Therefore, the purpose of this study is to identify baseline data for athletes and observe the relationship between ankle dorsiflexion measurements and non-contact lower extremity injuries. Ankle dorsiflexion can be defined as the degree as to which the dorsal portion of the foot can be brought closer to the tibia. A lack of ankle dorsiflexion can cause varied biomechanics and loading patterns which can lead to overcompensation resulting in possible injury. Objective: The purpose of this study is to determine the effect of ankle dorsiflexion range of motion on the presence of non-contact lower extremity injuries. We hypothesized that those who have a decreased ankle dorsiflexion ROM are at a greater risk of experiencing a non-contact lower extremity injury. Design: Prospective Cohort Study. Setting: Athletic Training Clinic at a mid-west NAIA institution. Patients or Other Participants: We tested a total of 315 athletes, college-aged students (122 females and 194 males; aged range = 17-23). Methods: Prior to the competitive sports season (fall 2019) ankle dorsiflexion ROM was recorded using the weight-bearing lunge test on 315 healthy college athletes. Participants measured for this study participated in football (n=117), men’s soccer (n=31), women’s soccer (n=28), women’s volleyball (n=26), co-ed cross country (n=36), co-ed cheerleading (n=20), dance team (n=7), women’s basketball (n=21), and wrestling (n=26). The Clinometer smart phone app was used to measure ankle dorsiflexion during the test. The smartphone was placed at 5 cm below the tibial tuberosity as the participant performed the lunge. Participants performed the weight-bearing lunge test three times on each leg and the average angle of the three trials was used for the data analysis. Athletes who had experienced a lower extremity injury in the previous six months were excluded from the study. The weight-bearing lunge test has been shown to have good intra-rater reliability (ICC =.712-.973; p=.036-Main Outcome Measures: Ankle dorsiflexion range of motion using the weight-bearing lunge test and non-contact lower extremity injuries. Results: Results were calculated using T-Tests using IBM SPSS software. There was a total of 38 injured and 237 uninjured athletes. There was no statistically significant (p = .656 ) in average ankle dorsiflexion between participants that were recorded as injured (42.30°) vs. Uninjured (46.69°). The correlation for asymmetry between the ankle dorsiflexion range of motion on the right leg vs. left leg between the injured (3.12°) vs. uninjured (9.48°) participants was also not statistically significant (p = .497) Conclusion: This study uses the weight-bearing lunge test to measure ankle dorsiflexion in the collegiate athletic population to find normative data. This normative data was used to determine if restricted ankle dorsiflexion caused an increased risk of lower extremity injuries. Our data showed no significant correlation between restricted ankle dorsiflexion and risk of injury to the lower extremities. There was also a lack of significance comparing asymmetry between the left and right leg in both injured and uninjured groups. Further research is needed to determine if restricted ankle dorsiflexion, measured with the weight-bearing lunge test, does or does not cause an increased risk of lower extremity injuries in the athletic population

The ACS Nearby Galaxy Survey Treasury

The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D<4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small & large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of ~10^4 in luminosity and star formation rate. The survey data consists of images taken with ACS on HST, supplemented with archival data and new WFPC2 imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. The new wide field imaging in ANGST reaches median 50% completenesses of m_F475W=28.0 mag, m_F606W=27.3 mag, and m_F814W=27.3 mag, several magnitudes below the tip of the red giant branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the structure in the red clump. The resulting photometric catalogs are publicly accessible and contain over 34 million photometric measurements of >14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both the ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.Comment: 54 pages, including 24 pages of figures and 16 pages of tables. Project website and data available at http://www.nearbygalaxies.org/ . Data is also available through MAST. Scheduled to appear in the Astrophysical Journal Supplements. (Replaced to fix several figures that were damaged during compression

The ACS Nearby Galaxy Survey Treasury I. The Star Formation History of the M81 Outer Disk

The ACS Nearby Galaxy Survey Treasury (ANGST) is a large Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) treasury program to obtain resolved stellar photometry for a volume-limited sample of galaxies out to 4 Mpc. As part of this program, we have obtained deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. The field contains the outskirts of a spiral arm as well as an area containing no current star formation. Our imaging results in a color-magnitude diagram (CMD) reaching to F814W = 28.8 and F606W = 29.5, one magnitude fainter than the red clump. Through detailed modeling of the full CMD, we quantify the age and metallicity distribution of the stellar populations contained in the field. The mean metallicity in the field is -1<[M/H]<0 and only a small fraction of stars have ages <~1 Gyr. The results show that most of the stars in this outer disk field were formed by z~1 and that the arm structure at this radius has a lifetime of >~100 Myr. We discuss the measured evolution of the M81 disk in the context of surveys of high-redshift disk galaxies and deep stellar photometry of other nearby galaxies. All of these indicate that massive spiral disks are mostly formed by z~1 and that they have experienced rapid metal enrichment.Comment: 26 pages, 2 tables, 18 figures, accepted for publication in A